On Jun 30, 2007, at 5:10 PM, Peter Krantz wrote:
>
> On 6/30/07, Philip TAYLOR <Philip-and-LeKhanh@royal-tunbridge-
> wells.org> wrote:
>> Why would you want to display the fallback content
>> at the same time as the image ? If both are to
>> be presented concurrently, the so-called "fallback"
>> content isn't fallback at all, but simply an intrinsic
>> part of the page (and would, of course, be marked up
>> as such).
>
> The description of a complex picture may be helpful to people without
> a disability. Why hide it in the fallback content and force editors to
> repeat the content elsewhere? If I make it part of the page, how would
> e.g. a screen reader know that the particular content is connected to
> the image?
>
> Why not make it possible to use CSS and script to modify the
> presentation of the description. An example could be that the user is
> able to click and slide out the description from underneath the image
> or choose to display it some other way.
I think you're discussing two different issues at the same time. 1)
How we recommend UAs (especially visual UAs) handle fallback content;
2) How one should author content that is not fallback content; and 3)
Whether fallback content is necessary if the author has already said
everything desired in the main content.
In terms of the first issue: yes, it may be desirable to have UAs
make fallback content available for viewing alongside the parent
content or to swap between the two. One use case I could imagine
would be someone with a visual impairment who is not totally blind.
Similarly, someone with a cognitive disability may benefit from
reading textual description of visual and aural media that is
otherwise difficult to comprehend.
On the second and third issues, an author may include lengthy prose
about embedded content and then the author may determine she has
nothing else to say in the fallback content. For example this author
may note be targeting an audience that requires any further
descriptive content. The media itself provides everything necessary
through its own fallback content such as closed captioning. Or as
I've stated before, we might recommend UAs extract description
metadata right out of an image and an author determines that metadata
description is sufficient for the audience's fallback content.. In
these cases the fallback would be left blank.
The HTML5 recommendation could eventually include some discussion of
these boundary issues and how authors might or might not require
fallback content. It also might be useful to provide specific
guidance to visual UAs on how they might present content with
fallback content combined or alternate between the two.
Take care,
Rob